Noble Gases and Vacuum
Nitto Kohki
The Nitto Kohki Cupla for noble gases and vacuum are designed for argon, nitrogen, helium and other inert gases as well as for the vacuum range down to -0.1 MPa. The PCV and SP-V-A series offer high tightness with low leak rates - essential for analytical technology, shielding-gas applications and vacuum processes where any leakage falsifies the result.
Stainless-steel bodies and special seal materials ensure resistance to inert gases and the required vacuum suitability. The valved design prevents gas entrapment and air ingress on disconnection and maintains the purity of the gas line.
Nitto Kohki Noble Gases & Vacuum - Cupla series
| Criterion | Nitto Kohki | Parker | Stäubli | Rectus |
|---|---|---|---|---|
| Vacuum capability | down to -0.1 MPa | partial | yes | no |
| Noble-gas suitability | Ar / N₂ / He | N₂, partial | yes | not standard |
| Leak rate | low | medium | low | not specified |
| Material | stainless steel | stainless/brass | stainless | brass/steel |
| Valve shut-off | Yes (SP-V-A) | partial | yes | limited |
| Pure-gas suitability | Yes | partial | yes | no |
| Series | Application | Pressure / vacuum | Key feature |
|---|---|---|---|
| PCV Cupla | gas and pipe lines | pressure range | check-valve / pipe-line function |
| SP-V-A Cupla | vacuum & noble gas | down to -0.1 MPa | valved, low leak rate |
Typical applications: shielding- and noble-gas supply (argon, nitrogen, helium), vacuum processes and distribution, analytical and laboratory technology, welding and coating systems with inert gas, and pure-gas lines requiring low leak rates.
Series in this category compared
Maximum working pressure is the first selection criterion. It decides the series, not the size: a low pressure coupling does not become high pressure capable by choosing a larger bore.
| Series | Max working pressure | Sizes | Shut-off type | Fluids | Body material | Catalogue page |
|---|---|---|---|---|---|---|
| PCV PIPE CUPLA | 45 bar | Copper pipe outside diameter 4.0 mm to 15.88 mm; end thread 1/4 inch and 3/8 inch | Valveless | Inert gas, Vacuum, Air, Gas | Brass | 151 |
| SP-V CUPLA Type A | 3.0 to 7.5 MPa {31 to 76 kgf/cm2} | 1/4 inch to 3/4 inch | Two-way shut-off | Inert gas, Vacuum, Gas, Air, Water | Brass (Standard material), Stainless steel (Standard material), Stainless steel (Made-to-order item) | 149 |
The four shut-off types
The shut-off type decides what happens on disconnection. It is the second criterion and depends on whether the line is under pressure when it is parted and how much fluid may escape.
Choosing a coupling in five steps
- Fix the fluid and the operating temperature, which gives the seal material.
- Determine the maximum working pressure, which gives the pressure class and the series.
- Choose the shut-off type: one-way, two-way, valveless or flat face.
- Fix the end connection and size: hose barb, male thread, female thread or tube fitter.
- Choose the body material for the fluid and the environment, then order plug and socket as a pair.
This page is based on the Nitto Kohki general catalogue Quick Connect Couplings C01en-b, 190 pages. The complete catalogue is available for download on this page.
